81 ^ 
Mr Hunter cm a/n hUproDed Self-Acting Pump. 
This self-acting pump may be applied to many uses. If a 
person has a spring which supplies his house with water at the 
level of the middle storey, he may place F in the kitchen, and C 
in the bed-room, and every gallon of water used in the kitchen,, 
will give a corresponding gallon (or very nearly so) in the bed-, 
room. 
In using this pump the pipe E may be supplied with impure 
or even very dirty water, and the whole of the spring B will be 
raised to C, instead of half of it being perhaps wasted at L ; and 
in this manner any spring may be pumped up to the requisite 
level without one drop being lost, merely by forming a dam 
or lead as in mills, and obtaining a fall for a part of the water 
equal to the height to which it is requisite to pump up the 
spring. 
It is not necessary that II should be on a level with B. It 
may be far above or below it, and the effect will be nearly the 
same. The water will rise as high above D as from R to S. 
The rain-water collected on the top of a house, will pump up a 
corresponding quantity of pure water from a well as deep as the 
house is high ; but this pump will be found most useful where a 
large body of water is to be raised through a small height. 
The great superiority of this pump consists in its acting al- 
most entirely without friction. 
A pump of the above dimensions (which are very diminutive) 
continued working without being touched for three months, and 
-raised eight hogsheads of water every day. 
Aet. 'KV .-^Account of a New Method of malcing Single 
Microscopes of Glass, proposed and executed by Thomas 
SivRiGHT, Esq., F. R. S. Edin. and F. A. S. E. Communi- 
cated by the Author. 
N ARIOUS methods have at different times been described, by 
means of which persons of ordinary ingenuity may construct for 
themselves single microscopes of a very high magnifying power, 
and possessing a very considerable degree of distinctness. 
VOL. I. NO, I. JUNE 1819 . 
F 
